Latest hist-immediate-drop patch

[Wayne Davison <wayned@xxxxxxxxxxxxxxxxxxxxx>]

Let me know if zsh's release is not imminent, 'cuz I think that this
patch should be added to zsh.  It's very addictive -- I can't imagine
trying to use zsh without it now.

This is an updated patch that fixes one minor non-desirable side-effect
(the history number is now decremented when the previous temporary line
is discarded, thus avoiding unneeded gaps in the value) and to tweak my
use of the "save" variable slightly.

Enjoy,

..wayne..

---8<------8<------8<------8<---cut here--->8------>8------>8------>8---
Index: Doc/Zsh/options.yo
@@ -544,18 +544,39 @@
 pindex(HIST_IGNORE_SPACE)
 cindex(history, ignoring spaces)
 item(tt(HIST_IGNORE_SPACE) (tt(-g)))(
-Do not enter command lines into the history list
-if the first character on the line is a space, or if one of
-the expanded aliases contained a leading space.
+Remove command lines from the history list when the first character on
+the line is a space, or when one of the expanded aliases contains a
+leading space.
+If tt(HIST_IMMEDIATE_DROP) is set, the line is dropped from the
+history right away, otherwise the command lingers in the internal
+history until the next command is entered before being dropped
+(allowing you to briefly reuse and/or edit the line).
 )
+pindex(HIST_IMMEDIATE_DROP)
+cindex(history, dropping lines)
+item(tt(HIST_IMMEDIATE_DROP))(
+When this option is set, dropped history lines are immediately lost.
+By default, the to-be-dropped history line lingers until the next
+command is typed, allowing you to briefly reuse and/or edit it.
+See also tt(HIST_IGNORE_SPACE), tt(HIST_NO_FUNCTIONS), and
+tt(HIST_NO_STORE).
+)
 pindex(HIST_NO_FUNCTIONS)
 item(tt(HIST_NO_FUNCTIONS))(
-Do not store function definitions in the history list.
+Remove function definitions from the history list.
+If tt(HIST_IMMEDIATE_DROP) is set, the line is dropped from the
+history right away, otherwise the function lingers in the internal
+history until the next command is entered before being dropped
+(allowing you to briefly reuse and/or edit the line).
 )
 pindex(HIST_NO_STORE)
 item(tt(HIST_NO_STORE))(
-Remove the tt(history) (tt(fc -l)) command from
-the history when invoked.
+Remove the tt(history) (tt(fc -l)) command from the history list
+when invoked.
+If tt(HIST_IMMEDIATE_DROP) is set, the line is dropped from the
+history right away, otherwise the command lingers in the internal
+history until the next command is entered before being dropped
+(allowing you to briefly reuse and/or edit the line).
 )
 pindex(HIST_REDUCE_BLANKS)
 item(tt(HIST_REDUCE_BLANKS))(
Index: Src/hashtable.c
@@ -1480,10 +1480,11 @@
     HashNode oldnode = addhashnode2(ht, nam, nodeptr);
     Histent he = (Histent)nodeptr;
     if (oldnode && oldnode != (HashNode)nodeptr) {
-	if (he->flags & HIST_MAKEUNIQUE
+	if (he->flags & (HIST_MAKEUNIQUE | HIST_TMPSTORE)
 	 || (he->flags & HIST_FOREIGN && (Histent)oldnode == he->up)) {
+	    (void) addhashnode2(ht, oldnode->nam, oldnode); /* restore hash */
 	    he->flags |= HIST_DUP;
-	    addhashnode(ht, oldnode->nam, oldnode); /* Remove the new dup */
+	    he->flags &= ~HIST_MAKEUNIQUE;
 	}
 	else {
 	    oldnode->flags |= HIST_DUP;
Index: Src/hist.c
@@ -794,16 +794,19 @@
 void
 histreduceblanks(void)
 {
-    int i, len, pos, needblank;
+    int i, len, pos, needblank, spacecount = 0;

-    for (i = 0, len = 0; i < chwordpos; i += 2) {
+    if (isset(HISTIGNORESPACE))
+	while (chline[spacecount] == ' ') spacecount++;
+
+    for (i = 0, len = spacecount; i < chwordpos; i += 2) {
 	len += chwords[i+1] - chwords[i]
 	     + (i > 0 && chwords[i] > chwords[i-1]);
     }
     if (chline[len] == '\0')
 	return;

-    for (i = 0, pos = 0; i < chwordpos; i += 2) {
+    for (i = 0, pos = spacecount; i < chwordpos; i += 2) {
 	len = chwords[i+1] - chwords[i];
 	needblank = (i < chwordpos-2 && chwords[i+2] > chwords[i+1]);
 	if (pos != chwords[i]) {
@@ -1044,8 +1047,10 @@
 	    } else
 		save = 0;
 	}
-	if (chwordpos <= 2 || should_ignore_line(prog))
+	if (chwordpos <= 2)
 	    save = 0;
+	else if (should_ignore_line(prog))
+	    save = -1;
     }
     if (flag & (HISTFLAG_DONE | HISTFLAG_RECALL)) {
 	char *ptr;
@@ -1058,14 +1063,23 @@
 	}
 	if (flag & HISTFLAG_RECALL) {
 	    zpushnode(bufstack, ptr);
-
 	    save = 0;
 	} else
 	    zsfree(ptr);
+    }
+    if (isset(HISTIGNORESPACE) && (save || *chline == ' ')) {
+	Histent he;
+	for (he = hist_ring; he && he->flags & HIST_FOREIGN;
+	     he = up_histent(he)) ;
+	if (he && he->flags & HIST_TMPSTORE) {
+	    if (he == hist_ring)
+		curline.histnum = curhist--;
+	    freehistnode((HashNode)he);
+	}
     }
-    if (save) {
+    if (save > 0 || (save < 0 && !isset(HISTIMMEDIATEDROP))) {
 	Histent he;
-	int keepflags;
+	int newflags;

 #ifdef DEBUG
 	/* debugging only */
@@ -1081,6 +1095,7 @@
 	    if (isset(HISTREDUCEBLANKS))
 		histreduceblanks();
 	}
+	newflags = save > 0? 0 : HIST_OLD | HIST_TMPSTORE;
 	if ((isset(HISTIGNOREDUPS) || isset(HISTIGNOREALLDUPS)) && hist_ring
 	 && histstrcmp(chline, hist_ring->text) == 0) {
 	    /* This history entry compares the same as the previous.
@@ -1089,18 +1104,16 @@
 	     * timestamp right.  Perhaps, preserve the HIST_OLD flag.
 	     */
 	    he = hist_ring;
-	    keepflags = he->flags & HIST_OLD; /* Avoid re-saving */
+	    newflags |= he->flags & HIST_OLD; /* Avoid re-saving */
 	    freehistdata(he, 0);
 	    curline.histnum = curhist;
-	} else {
-	    keepflags = 0;
+	} else
 	    he = prepnexthistent();
-	}

 	he->text = ztrdup(chline);
 	he->stim = time(NULL);
 	he->ftim = 0L;
-	he->flags = keepflags;
+	he->flags = newflags;

 	if ((he->nwords = chwordpos/2)) {
 	    he->words = (short *)zalloc(chwordpos * sizeof(short));
@@ -1893,8 +1906,10 @@
 	    } else
 		he->words = (short *)NULL;
 	    addhistnode(histtab, he->text, he);
-	    if (hist_ring != he)
-		curhist--; /* We discarded a foreign duplicate */
+	    if (he->flags & HIST_DUP) {
+		freehistnode((HashNode)he);
+		curhist--;
+	    }
 	}
 	if (start && readflags & HFILE_USE_OPTIONS) {
 	    zsfree(lasthist.text);
@@ -1962,7 +1977,8 @@
     if (out) {
 	for (; he && he->histnum <= xcurhist; he = down_histent(he)) {
 	    if ((writeflags & HFILE_SKIPDUPS && he->flags & HIST_DUP)
-	     || (writeflags & HFILE_SKIPFOREIGN && he->flags & HIST_FOREIGN))
+	     || (writeflags & HFILE_SKIPFOREIGN && he->flags & HIST_FOREIGN)
+	     || he->flags & HIST_TMPSTORE)
 		continue;
 	    if (writeflags & HFILE_SKIPOLD) {
 		if (he->flags & HIST_OLD)
Index: Src/options.c
@@ -130,6 +130,7 @@
 {NULL, "histignorealldups",   0,			 HISTIGNOREALLDUPS},
 {NULL, "histignoredups",      0,			 HISTIGNOREDUPS},
 {NULL, "histignorespace",     0,			 HISTIGNORESPACE},
+{NULL, "histimmediatedrop",   0,			 HISTIMMEDIATEDROP},
 {NULL, "histnofunctions",     0,			 HISTNOFUNCTIONS},
 {NULL, "histnostore",	      0,			 HISTNOSTORE},
 {NULL, "histreduceblanks",    0,			 HISTREDUCEBLANKS},
Index: Src/zsh.h
@@ -1252,6 +1252,7 @@
 #define HIST_READ	0x00000004	/* Command was read back from disk*/
 #define HIST_DUP	0x00000008	/* Command duplicates a later line */
 #define HIST_FOREIGN	0x00000010	/* Command came from another shell */
+#define HIST_TMPSTORE	0x00000020	/* Kill when user enters another cmd */

 #define GETHIST_UPWARD  (-1)
 #define GETHIST_DOWNWARD  1
@@ -1367,6 +1368,7 @@
     HISTIGNOREALLDUPS,
     HISTIGNOREDUPS,
     HISTIGNORESPACE,
+    HISTIMMEDIATEDROP,
     HISTNOFUNCTIONS,
     HISTNOSTORE,
     HISTREDUCEBLANKS,
---8<------8<------8<------8<---cut here--->8------>8------>8------>8---